Invited Speaker The 48th Lorne Conference on Protein Structure and Function 2023

High-speed atomic force microscopy for dynamic single molecule structural biology   (#51)

Simon Scheuring 1 2
  1. Department of Anesthesiology, Weill Cornell Medicine, New York, NY, United States
  2. Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY, USA

High-speed atomic force microscopy (HS-AFM) is a powerful technique that provides dynamic movies of biomolecules at work. We successfully used HS-AFM to take movies and determine dynamics of membrane trafficking systems, transporters and channels. To break current temporal resolution limitations to characterize single molecule kinetics, we developed HS-AFM line scanning (HS-AFM-LS) and HS-AFM height spectroscopy (HS-AFM-HS), methods whereby we scan the HS-AFM tip along a single scan line or keep it at a fixed position, and detect the motions of the molecules under the tip with sub-nanometer spatial and millisecond to microsecond temporal resolution, respectively [1,2]. To break resolution limitations, we developed Localization AFM (LAFM) by applying localization image reconstruction algorithms to peak positions in AFM data and increased the resolution beyond the limits set by the tip radius to reach near-atomic resolution on soft protein surfaces in close-to-native conditions [3]. Here, I will review these recent achievements, and present novel data where we exploit these new possibilities to characterize membrane protein structure-dynamics. We reason that the progress of AFM must comprise two axes: (i) Making AFM/HS-AFM a better (faster, higher resolution) tool, and (ii) making AFM/HS-AFM data an integrated part of the structural biology / molecular biophysics toolbox. Therefore, we develop data analysis and interpretation methods that interface with cryo-EM and X-ray crystallography, where HS-AFM can contribute the urgently needed information about structure, dynamics and conformations under close-to-native conditions.